I went to a low profile gas block so this is no longer needed. I can include the sight post but I have no detent or spring. This sight has been milled .030 on the rear face so it will work with a retaining ring or without. DPMS made this originally to only fit with free float hand guards so when a ring was added the gas port would not line up enough for sufficient gas power. Works perfectly looks lie new and I believe these are discontinued. $40 shipped. Paypal accepted